# qml.pauli.PauliSentence¶

class PauliSentence[source]

Bases: dict

Dictionary representing a linear combination of Pauli words, with the keys as PauliWord instances and the values correspond to coefficients.

>>> ps = PauliSentence({
PauliWord({0:'X', 1:'Y'}): 1.23,
PauliWord({2:'Z', 0:'Y'}): -0.45j
})
>>> ps
1.23 * X(0) @ Y(1)
+ (-0-0.45j) * Z(2) @ Y(0)

 wires Track wires of the PauliSentence.
wires

Track wires of the PauliSentence.

 simplify([tol]) Remove any PauliWords in the PauliSentence with coefficients less than the threshold tolerance. to_mat(wire_order[, format]) Returns the matrix representation.
simplify(tol=1e-08)[source]

Remove any PauliWords in the PauliSentence with coefficients less than the threshold tolerance.

to_mat(wire_order, format='dense')[source]

Returns the matrix representation.

Keyword Arguments
• wire_order (iterable or None) – The order of qubits in the tensor product.

• format (str) – The format of the matrix (“dense” by default), if not a dense matrix, then the format for the sparse representation of the matrix.

Returns

Matrix representation of the PauliSentence.

Return type

(Union[NumpyArray, ScipySparseArray])

Rasies:

ValueError: Can’t get the matrix of an empty PauliSentence.

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